1. Technical Field
The present invention is an apparatus for controlling flow into a compressor, and more particularly is a control and a valve for controlling air intake when a compressor is started.
2. Background Art
A rotary screw compressor has a pair of parallel rotors which are rotated oppositely relative to each other by a prime mover, such as an internal combustion engine or an electric motor. The rotors have intermeshed oppositely-pitched helical lands and grooves. Operation of a compressor creates a negative pressure which draws fluid between the rotors and into the grooves. Air in the grooves is compressed when the intermeshed rotors rotate. Compressed air discharges from the grooves and is stored in a receiver tank. A prime mover in some conditions of starting (e.g., cold weather) is not able to supply sufficient torque to rotate the rotors in the compressor unless the prime mover is adequately warmed-up or the load imposed by the compressor is reduced. Air flow into a compressor during starting increases the torque required to start the compressor and results in the application of an increased reaction force to the prime mover which opposes acceleration of the prime mover. Load on a prime mover, such as an internal combustion engine, can prevent the prime mover from starting or from quickly warming-up. It therefore is desirable to reduce the air flow into a compressor during starting to facilitate starting and warm-up of a prime mover which drives the compressor. Control systems, valves, and timing devices have been proposed for controlling flow intake when a compressor is started. Prior flow intake control devices do not adequately restrict flow into a compressor during starting.